MappedSuperclass


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7    * You can obtain a copy of the license at 
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9    * glassfish/bootstrap/legal/CDDLv1.0.txt.
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13   * When distributing Covered Code, include this CDDL 
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15   * at glassfish/bootstrap/legal/CDDLv1.0.txt.  
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18   * you own identifying information: 
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20   * 
21   * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
22   */
23  package javax.persistence;
24  
25  import java.lang.annotation.Target  ;
26  import java.lang.annotation.Retention  ;
27  import static java.lang.annotation.ElementType.TYPE  ;
28  import static java.lang.annotation.RetentionPolicy.RUNTIME  ;
29  
30  /**
31   * Designates a class whose mapping information is applied 
32   * to the entities that inherit from it. A mapped superclass 
33   * has no separate table defined for it.  
34   *
35   * <p> A class designated with the <code>MappedSuperclass</code> 
36   * annotation can be mapped in the same way as an entity except that the 
37   * mappings will apply only to its subclasses since no table 
38   * exists for the mapped superclass itself. When applied to the 
39   * subclasses the inherited mappings will apply in the context 
40   * of the subclass tables. Mapping information may be overridden 
41   * in such subclasses by using the {@link AttributeOverride} and 
42   * {@link AssociationOverride} annotations or corresponding XML elements.
43   *
44   * <pre>
45   *    Example: Concrete class as a mapped superclass
46   *
47   *    &#064;MappedSuperclass
48   *    public class Employee {
49   *    
50   *        &#064;Id protected Integer empId;
51   *        &#064;Version protected Integer version;
52   *        &#064;ManyToOne &#064;JoinColumn(name="ADDR")
53   *        protected Address address;
54   *    
55   *        public Integer getEmpId() { ... }
56   *        public void setEmpId(Integer id) { ... }
57   *        public Address getAddress() { ... }
58   *        public void setAddress(Address addr) { ... }
59   *    }
60   *    
61   *    // Default table is FTEMPLOYEE table
62   *    &#064;Entity
63   *    public class FTEmployee extends Employee {
64   *    
65   *        // Inherited empId field mapped to FTEMPLOYEE.EMPID
66   *        // Inherited version field mapped to FTEMPLOYEE.VERSION
67   *        // Inherited address field mapped to FTEMPLOYEE.ADDR fk
68   *        
69   *    
70   *    // Defaults to FTEMPLOYEE.SALARY
71   *    
72   *    protected Integer salary;
73   *    
74   *    
75   *    public FTEmployee() {}
76   *    
77   *    
78   *    public Integer getSalary() { ... }
79   *    
80   *    public void setSalary(Integer salary) { ... }
81   *    }
82   *    
83   *    &#064;Entity &#064;Table(name="PT_EMP")
84   *    &#064;AssociationOverride(name="address", 
85   *    
86   *    
87   *    joincolumns=&#064;JoinColumn(name="ADDR_ID"))
88   *    public class PartTimeEmployee extends Employee {
89   *    
90   *        // Inherited empId field mapped to PT_EMP.EMPID
91   *        // Inherited version field mapped to PT_EMP.VERSION
92   *        // address field mapping overridden to PT_EMP.ADDR_ID fk
93   *        &#064;Column(name="WAGE")
94   *        protected Float hourlyWage;
95   *    
96   *        public PartTimeEmployee() {}
97   *    
98   *        public Float getHourlyWage() { ... }
99   *        public void setHourlyWage(Float wage) { ... }
100  *    }
101  *
102  *    Example: Non-entity superclass
103  *
104  *    public class Cart {
105  *    
106  *        // This state is transient
107  *        Integer operationCount;
108  *    
109  *        public Cart() { operationCount = 0; }
110  *        public Integer getOperationCount() { return operationCount; }
111  *        public void incrementOperationCount() { operationCount++; }
112  *    }
113  *    
114  *    &#064Entity
115  *    public class ShoppingCart extends Cart {
116  *    
117  *        Collection<Item> items = new Vector<Item>();
118  *    
119  *        public ShoppingCart() { super(); }
120  *    
121  *    
122  *    ...
123  *    
124  *        &#064OneToMany
125  *        public Collection<Item> getItems() { return items; }
126  *        public void addItem(Item item) {
127  *            items.add(item);
128  *            incrementOperationCount();
129  *        }
130  *    }
131  * </pre>
132  *
133  * @since Java Persistence 1.0
134  */
135 @Target  ({TYPE})
136 @Retention  (RUNTIME)
137 
138 public @interface MappedSuperclass {
139 }
140
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